Four men jailed for life for the murder of a Leeds teenager have lost an appeal against their convictions.

The men had been convicted of killing Tyrone Clarke, 16, who died after being attacked by a mob of up to 20 youths in Beeston in April 2004.

Islamur Rahman, 21, was given a minimum term of 12 years; Anjum Amin and Kamer Akram, both 22, a minimum of 11 and Liaquat Ali, 17, a minimum of nine.

Appeal Court judges decided on Friday the original convictions were safe.

Tyrone, who was of mixed race, was stabbed three times as he and his friend Raffael Lovick, 18, were chased by a group of Asian youths.

'Joint enterprise'

The gang cornered Tyrone in Brett Gardens, Beeston, and attacked him with makeshift weapons, including baseball bats, poles and planks of wood.

The trial judge said he did not consider it had been a racial attack.

The court had heard it was probable none of the four had struck the fatal blow. But they were convicted on the grounds of "joint enterprise".

At the Court of Appeal, Lord Justice Hooper - sitting with Mr Justice Gibbs and Mr Justice Roderick Evans - said: "It was their case that the knifeman was acting beyond the scope of any joint enterprise to attack Clarke.

"So, while the knifeman might have been guilty of murder, the others were not criminally responsible for that stabbing."

In his defence Rahman maintained that, although involved in the earlier confrontation with Clarke, he had never reached the area where the fatal attack occurred.

'Curiosity'

Akram said he likewise never reached the scene because he was "frustrated" by the arrival of the police.

Amin testified that he was "never anything more than a spectator" and that he also never reached the murder scene.

Ali said he was on his way to work when the attack in Brett Gardens occurred, that he took a look "simply out of curiosity" and then fled.

Lawyers for the four men argued that the trial judge misdirected the jury on the question of the actual knifeman's murderous intent when addressing them on the issue of joint enterprise.